Check the system

Abstract

The inspection system (1) comprises: a hollow probe (12) extending in a rod shape along a central axis (11) and rotating around the central axis; an optical system (30) supplying inspection laser light along the central axis via the probe and receiving reflected light from the surface of the inspected object returned along the central axis; an optical element (50) which emits the inspection laser light toward the inspected object relative to the central axis by means of an opening (13) at the front end of the probe and guides the reflected light in the direction of the central axis; and a gas supply system (80) which allows gas (89) to pass through the probe and be discharged from the opening.

Description

Technical Field

[0001] The present invention relates to an inspection system for inspecting a surface of an object by irradiating an inspection laser from an inspection head. Background Art

[0002] Japanese Patent Gazette No. 2007-315821 describes a surface inspection device, which uses a driving mechanism to rotate an axial inspection head with a reflector at the front end around an axis while moving along the axis, and uses the reflector to change the optical path of inspection light incident on the inspection head along the axis, irradiates the inspection object with the changed optical path, and detects the surface condition of the inspection object based on the amount of inspection light reflected by the inspection object and incident on the inspection head again, wherein the inspection head comprises: a head main body, which is mounted on the driving mechanism; and a holding portion, which is configured to be able to load and unload relative to the head main body and to hold the reflector. Summary of the invention

[0003] In an inspection head having a hollow probe, it is pointed out that dirt adheres to the optical system of the inspection head, which may hinder the surface inspection of the inspection object (object to be inspected) due to the reduction in inspection accuracy and the time required to remove the dirt.

[0004] One technical solution of the present invention is an inspection system, which has: a hollow probe extending in a rod shape along a central axis and rotating around the central axis; an optical system that supplies inspection laser along the central axis through the probe and receives reflected light from the surface of the inspected object returned along the central axis; an optical element that emits the inspection laser toward the inspected object relative to the central axis by means of an opening at the front end of the probe and guides the reflected light in the direction of the central axis; and a gas supply system that discharges gas through the probe from the opening. By supplying gas such as air to the inside of the probe having an opening at the front end and discharging it from the opening, contamination of the optical element provided at the front end of the probe can be suppressed. Moreover, contamination of the optical system via the probe can be prevented in advance. Therefore, the inspection system can be protected from dirt that is the main cause of contamination, such as dust, existing on the surface of the inspected object or the inspection object. Therefore, according to the inspection system, the surface of the inspection object can be inspected with high precision and stability.

[0005] The inspection system may also include: a holder that supports the probe, the holder being driven to rotate; an inner cylinder that is hollow and arranged coaxially with the holder inside the holder, with a bearing unit disposed between the inner cylinder and the holder; and a non-rotating optical fiber (optical fiber bundle) that is inserted into the probe via the inner cylinder. The gas supply system may also include a gas supply path that is connected in a manner that avoids interference with the bearing unit and allows the fluid to flow through the probe via the inner cylinder.

[0006] The inspection system may also include: a cylindrical sheath tube that covers the optical fiber and is connected to the inner cylinder via a sleeve; and a lens that is mounted on the front end of the sheath tube. The gas supply path may also include a connection path that connects the interior of the inner cylinder part to the inner side of the probe and the outer side of the sheath tube by partially removing the sleeve.

[0007] The inspection system may also include a driving unit, such as a motor, for rotating the inspection head including the probe around the central axis. Alternatively, the object to be inspected may include a hollow portion for the probe to be inserted, and the inspection system may further include a moving unit for relatively moving the probe and the object to be inspected along the central axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view showing the outline of the inspection device.

[0009] Figure 2 It is a cross-sectional view (II-II cross-sectional view) showing a schematic structure of the inspection device.

[0010] Figure 3 is a cross-sectional view showing a schematic structure of the inspection head. Figure 3 (a) The main structural components are indicated by cross-hatching. Figure 3 (b) shows the path of the purge air with hatching.

[0011] Figure 4 It is a magnified representation Figure 3 A cross-sectional view of the structure of the front end of the inspection head is shown.

[0012] Figure 5 It is a diagram showing the supply path that penetrates the sleeve. DETAILED DESCRIPTION

[0013] exist Figure 1 In FIG. 1 , the appearance of the inspection device (inspection system) 1 is shown. Figure 2 , a schematic structure of the inspection device 1 is shown in cross section. The inspection device (surface inspection device) 1 is suitable for inspecting the shape or state of the inner surface 4 of a hollow portion 3 such as a hole or a recess provided in an inspection object 2.

[0014] The inspection device 1 includes: a hollow inspection head 10, which extends in a rod shape along a central axis 11; a driving unit (rotation unit) 20, which rotates the inspection head 10 around the central axis 11; an optical system 30, which supplies a laser for inspection along the central axis 11 through the inspection head 10, and receives reflected light from the surface 4 of the inspected object 2 along the central axis 11; a moving unit 25, which moves the inspection head 10 and the inspected object 2 relative to each other along the central axis 11; and a housing 5, which houses the rotation unit 20, the optical system 30 and the moving unit 25.

[0015] The inspection device 1 includes a moving unit 25 that moves the inspection head 10 relative to the inspection object 2. The moving unit 25 in this example includes a carriage 28 on which the inspection head 10, the rotation unit 20, and the optical system 30 are mounted, and a slide 28 that moves the slide 28 forward and backward ( Figure 2 The structure of the moving unit 25 is an example, and it may be a slide, a moving table, etc. The moving unit 25 moves the inspection head 10 to a position P1 protruding forward from the housing 5 and a position P2 where the inspection head 10 is retracted into the housing 5. Instead of moving the inspection head 10 forward and backward, a robot or the like may be used to move the inspection object 2, or the inspection head 10 may be moved forward and backward and the inspection object 2 may be moved.

[0016] The inspection device 1 has a support unit 70 that is fixed to the carriage 28 of the moving unit 25 and supports the inspection head 10 from the inside. The inspection head 10 includes a holder 18 that is mounted in a rotatable manner relative to the fixed support unit 70 and a hollow probe 12 that protrudes from the holder 18 toward the front 6 along the central axis (rotation axis, shaft center) 11.

[0017] An example of the rotating unit 20 that drives the holder 18 to rotate is a motor 21 mounted on the carriage 28. The pulley 22 driven by the motor 21 is connected to the holder 18, which is the rotating part of the inspection head 10, by means of a drive belt (timing belt) 23, and the motor 21 rotates the holder 18 of the inspection head 10 at a high speed around the central axis 11 (with the central axis 11 as the rotation center) by means of the drive belt 23. Therefore, the probe 12 fixed to the holder 18 also rotates at a high speed, for example, 2000 rpm.

[0018] The optical system 30 includes a semiconductor laser (laser diode, LD) 31 that generates laser light for inspection, a light receiving element (such as a photodiode, CCD, CMOS, etc.) 32 that receives reflected light, and a control unit 33 including a drive circuit for the semiconductor laser 31 and a circuit for processing the signal received by the light receiving element 32. The signal received by the optical system 30 is sent to a computer (personal computer) not shown in the figure by means of the control unit 33, and then data processing is performed and used for analyzing the surface 4 of the object to be inspected 2. The optical system 30 also includes an optical fiber 35 inserted into the interior of the probe 12.

[0019] The inspection device 1 further includes a gas supply system (air supply system) 80 for supplying air as gas to the inside of the probe 12 by means of a support unit 70 fixed to the slide 28. The air source may be compressed air for control in the factory, or an air source such as an air bottle or a compressor that generates compressed air may be prepared near the inspection device 1. The air supplied by the air supply system 80 is preferably air with less impurities such as oil and moisture removed by a filter or a dryer. The gas supplied by the gas supply system 80 may also be an inert gas such as nitrogen or argon.

[0020] exist Figure 3 In the figure, a combination 90 of the inspection head 10 and the support unit 70 supporting the inspection head 10 is extracted and its schematic structure is shown in cross section. Figure 3 (a) shows the internal structure with a cross section. Figure 3 (b) shows the gas supply paths (air supply paths) 81 to 87 for supplying air 89 as gas by hatching. Figure 4 In FIG. 1 , the structure of the probe 12 at the front end of the inspection head 10 is shown in an enlarged cross section.

[0021] The inspection head 10 is a hollow cylindrical body extending along the rotation axis 11 as a whole, and the inspection head 10 is rotatably mounted on the same axis with respect to the non-rotating support unit 70 as a base by means of a bearing unit 17. The inspection head 10 includes: a cylindrical holder (holding part, rotating part) 18, which is rotatably mounted on the outside of the non-rotating inner cylinder part 71 of the support unit 70 by means of the bearing unit 17; and a hollow probe (insertion part, needle part) 12, which is supported by the holder 18 and extends from the holder 18 toward the front end (front) along the central axis 11. The support unit 70 supporting the inspection head 10 includes: an inner cylinder part 71, which is hollow and is set coaxially with the holder 18 inside the holder 18, and a bearing unit 17 is arranged between the holder 18 and the holder 18; and a hollow support cylinder 73, which is connected to the base end (opposite side to the probe 12) of the inner cylinder part 71.

[0022] The holder 18 includes a relatively thick driving portion 15 that transmits a rotational force by means of a driving belt 23, a connecting portion (jacket) 16 that supports the probe 12 extending forward, and a flange portion 14 that presses the jacket 16. The inspection head 10 has an opening (notch) 13 facing the radial direction at the front end 12a of the probe 12 extending from the center of the flange portion 14 of the holder 18 toward the front end (front). The optical system 30 is configured such that a laser (probe light) 61 for inspection is emitted toward the surface 4 of the hollow portion 3 of the object to be inspected 2 by means of the opening 13 provided at the front end 12a of the probe 12, and a reflected light 62 from the surface 4 of the object to be inspected 2 is returned from the probe 12 to the inspection head 10.

[0023] An optical fiber (fiber bundle) 35 for guiding the probe light 61 and the reflected light 62 is inserted inside the inspection head 10 along the central axis 11. The fiber bundle 35 is a bundle of multiple optical fibers, and may also include a light-emitting fiber 35a for guiding the probe light 61 emitted from the LD 31 toward the object to be inspected 2 and a light-receiving fiber 35b for guiding the reflected light 62 from the object to be inspected 2 toward the light-receiving element 32.

[0024] Furthermore, the inspection device 1 includes a cylindrical sheath (holding tube) 34 that holds the optical fiber 35 in a bundled state inside the inspection head 10. A lens 36 is installed at the front end of the sheath 34. The sheath 34 passes through the rotating probe 12 and the interior of the holder 18 along the central axis 11 in a non-rotating manner, and is connected to the inner cylinder 71 of the non-rotating support unit 70 by means of a sleeve 75. Moreover, the optical fiber 35 passes through the inner cylinder 71 and the support tube 73 and is connected to the semiconductor laser 31 and the light receiving element 32 at the rear. Therefore, in the inspection head 10, the sheath 34 and the optical fiber 35 do not rotate, and the outer inspection head 10 rotates, thereby, the inspection light 61 is emitted toward the surface of the hollow part 3 while rotating by means of the optical element 50 at the front end 12a of the probe 12.

[0025] The probe 12 extends forward from the flange portion 14 of the holder 18 along the central axis 11, and an optical element 50 for controlling the emission direction of the probe light 61 is installed at the front end (near the front end) 12a. An example of the optical element 50 is a plane mirror, and it can also be other optical elements such as a prism that have a reflecting surface or a refractive surface that can control the emission direction and incident direction of light. In the inspection device 1 of this example, the angle of the mirror surface (reflecting surface) 51 of the optical element 50 is set to 45 degrees, so that the probe light 61 emitted from the optical fiber 35 with the central axis 11 as the optical axis is emitted in a direction orthogonal to the central axis (optical axis) 11. In addition, the mirror surface 51 of the optical element 50 is used to reflect the light (reflected light) 62 reflected from the inner surface 4 of the inspection object in the direction of the optical fiber 35 of the central axis 11.

[0026] An example of the lens 36 mounted on the front end of the sheath tube 34 is an objective lens (photochromic mirror) having an appropriate focal length, which focuses the probe light 61 output from the front end of the optical fiber 35 toward the inspection target surface 4 via the reflection surface 51. The photochromic mirror 36 also includes a function of focusing the reflected light 62 introduced into the inspection head 10 via the reflection surface 51 toward the front end of the optical fiber 35. The optical system 30 that supplies the probe light 61 along the central axis 11 of the inspection head 10 and detects the reflected light 62 is not limited to the optical fiber 35, and may be other optical systems known as optical pickups, etc., including a dichroic prism or the like.

[0027] The inspection device 1 further includes a gas supply system 80 for supplying a purge gas, typically air 89, to the interior of the probe 12. Figure 3 In (b), the gas supply paths (air supply paths) 81 to 87 constituting the gas supply system (air supply system) 80 are shown by hatching. The air supply system 80 includes: a first supply path 81 that passes through the outer block 73a of the support cylinder 73 of the fixed support unit 70; a buffer area 81a that is formed between the support cylinder 73 and the hollow inner block 73b; and a second supply path 82 that passes through the inner block 73b and connects the buffer area 81a to the inside of the inner block 73b, that is, the inside of the support cylinder 73. The air 89 supplied to the inside of the support cylinder 73 (the inside of the inner block 73b) by these supply paths 81 to 82 flows through the gap between the inside of the support cylinder 73 and the optical fiber 35 as the third supply path 83, and flows through the gap between the inside of the inner cylinder 71 of the support unit 70 and the optical fiber 35 as the fourth supply path 84.

[0028] like Figure 5 As shown, the air supply system 80 also includes a connection path (fifth supply path) 85, which connects the flow path 84 inside the inner tube 71 with the area 86 inside the probe 12 and outside the sheath 34 by removing part of the sleeve 75 connecting the sheath 34 to the inner tube 71 of the support unit 70. Therefore, the purge air 89 is supplied from the fourth supply path 84 inside the inner tube 71 to the sixth supply path 86 inside the probe 12 via the connection path 85. Figure 5 In the embodiment, the connection path 85 is formed by partially removing the inner side of the sleeve 75, but the connection path 85 can also be formed by partially removing the outer side of the sleeve 75, or the connection path 85 can also be formed by removing the boundary portion between the inner side of the inner tube portion 71 and the sleeve 75.

[0029] Inside the probe 12, the purge air 89 flows in the flow path (the 6th supply path) 86 outside the sheath 34, and is supplied to the space (the 7th supply path) 87 in front of (the front end) of the photochromic mirror 36 installed at the front end of the sheath 34. Moreover, the purge air 89 is discharged to the outside from the opening 13 at the front end of the probe 12. By supplying the purge air 89 to the probe 12, it is possible to prevent the optical element 50, the lens 36, the optical fiber 35, etc. equipped inside the probe 12 from being contaminated by dust and the like invading from the opening 13, thereby reducing the optical performance. It is also possible to cover the opening 13 with a translucent material to prevent the intrusion that is the main cause of contamination, but the translucent material covering the opening 13 is likely to be contaminated and the optical performance is reduced. In addition, refraction of light caused by the translucent material may occur, and if an attempt is made to increase the rotation speed of the probe 12 to shorten the surface inspection time, it will become the main cause of the reduction in the accuracy of the inspection device 1.

[0030] By supplying purge air 89 to the interior of the probe 12 and discharging it from the open opening 13, it is possible to suppress the reduction in optical performance caused by covering the opening 13. Moreover, it is possible to suppress the intrusion of impurities from the opening 13 into the interior of the probe 12. In addition, by providing the flow of air 89 in the probe 12, it is also possible to suppress the adhesion of dirt to the optical equipment inside the probe 12. Therefore, the rotation speed of the probe 12 can be increased, and the time for surface inspection can be shortened. In addition, the time required for cleaning the optical equipment inside the probe 12 can be saved or shortened, so the frequency of maintenance can be reduced, and surface inspection can be performed more efficiently.

[0031] In addition, the inspection head 10 including the probe 12 is rotatably mounted on the outside of the fixed support unit 70 including the inner cylinder portion 71 via the bearing unit 17. Therefore, the supply paths 81 to 85 of the purge air 89 can be arranged from the support unit 70 fixed inside to the inside of the probe 12 via the support cylinder 73 and the inner cylinder portion 71. Therefore, the air supply system 80 of a simple structure that introduces the purge air 89 into the inside of the probe 12 of the inspection head 10 via the fixed support unit 70 can be provided.

[0032] Furthermore, inside the probe 12, a supply path 86 is provided outside the sheath tube 34 that accommodates the optical fiber 35, and at the front end of the sheath tube 34, a lens 36 is provided inside the probe 12 in a structure independent of the probe 12. Therefore, the passage of the purge air 89 will not be blocked by the lens 36 inside the probe 12, and all surfaces including the lens 36 exposed inside the probe 12 can be covered by the purge air 89, thereby suppressing contamination caused by dirt on the optical system 30, especially on the optical system 30 provided inside the probe 12 for inputting and outputting light.

[0033] In the above description, an inspection system is disclosed, which has: a hollow inspection head, which extends in a rod shape along a central axis and rotates around the central axis; and an optical system, which supplies inspection laser along the central axis through the inspection head and receives reflected light from the surface of the inspected object that returns along the central axis. The inspection head includes: a holder, which is driven to rotate; a hollow probe, which extends from the holder along the central axis; and an optical element, which is arranged at the front end of the probe, and with the help of an opening at the front end of the probe, the inspection laser is emitted toward the inspected object and the reflected light is guided toward the central axis relative to the central axis. The inspection system also has an air supply system that supplies air to the interior of the probe and exhausts air from the opening.

[0034] Alternatively, the inspection system further includes a non-rotating support unit that supports the inspection head from the inside, the support unit including: an inner cylinder portion, which is hollow and is arranged coaxially with the retaining member inside the retaining member, with a bearing unit arranged between the inner cylinder portion and the retaining member; and a hollow support cylinder connected to the base end of the inner cylinder portion, the optical system includes an optical fiber bundle that is inserted into the probe with the aid of the support cylinder and the inner cylinder portion, and is a non-rotating optical fiber bundle, and the air supply system includes an air supply path that is connected in such a manner that a fluid flows in the probe with the aid of the support cylinder and the inner cylinder portion.

[0035] Alternatively, the inspection system further includes: a cylindrical sheath tube, which covers the optical fiber bundle and is connected to the inner cylinder portion by means of a sleeve; and a photochromic mirror, which is mounted on the front end of the sheath tube, and the air supply path includes a connection path, which connects the interior of the inner cylinder portion with the inner side of the probe and the outer side of the sheath tube by partially removing the sleeve. Alternatively, the inspection system further includes a rotating unit for rotating the inspection head around the central axis. In addition, the object to be inspected may include a hollow portion for inserting the probe, and the inspection system further includes a moving unit for moving the inspection head and the object to be inspected relative to each other along the central axis.

[0036] In addition, in the above description, a specific embodiment of the present invention is described, but a person skilled in the art can think of various other embodiments and modifications without departing from the scope and spirit of the present invention. Such other embodiments and modifications are the objects protected by the following claims, and the present invention is limited by the following claims.

Claims

1. An inspection system (1), wherein: The inspection system has: A hollow probe (12) extending from a holder (18) along a central axis (11) in a rod-like shape and rotating together with the holder about the central axis, the holder being driven to rotate; a hollow, non-rotating inner cylinder (71) which is arranged inside the retaining member and coaxial with the retaining member, and a bearing unit (17) is arranged between the retaining member and the inner cylinder; a cylindrical non-rotating sheath tube (34) which penetrates the interior of the probe and the holder along the central axis, the sheath tube covers the optical fiber bundle (35) and is connected to the inner cylinder portion via a sleeve (75); an optical system (30) which supplies inspection laser light (61) along the central axis via the probe and receives reflected light (62) from the surface of the inspection object returned along the central axis via the optical fiber via a lens (36) installed at the front end of the sheath tube; an optical element (50) which emits the inspection laser toward the object to be inspected relative to the central axis by means of an opening (13) at the front end of the probe and guides the reflected light in the direction of the central axis; and A gas supply system (80) supplies compressed gas (89) to an area (86) on the outside of the sheath tube and on the inside of the probe rotating at a high speed relative to the sheath tube through a gas supply path, the gas supply path introduces the gas with the aid of the inner cylinder portion, and includes a connecting path (85) that connects the interior of the inner cylinder portion with the area by partially removing the sleeve, the area covering the entire outside of the sheath tube in the probe, and the gas is discharged from the opening at the front end of the probe that emits the laser and guides the reflected light.

2. The inspection system according to claim 1, wherein: The inspection system also has a driving unit that rotates an inspection head including the probe around the central axis.

3. The inspection system according to claim 1 or 2, wherein: The object to be inspected includes a hollow portion for the probe to be inserted into, The inspection system further includes a moving unit that relatively moves the probe and the inspection object along the central axis.

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